-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0000935836-10-000001.txt : 20100104
<SEC-HEADER>0000935836-10-000001.hdr.sgml : 20100101
<ACCEPTANCE-DATETIME>20100104172513
ACCESSION NUMBER:		0000935836-10-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20091230
FILED AS OF DATE:		20100104
DATE AS OF CHANGE:		20100104

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			KENT BRADLEY R
		CENTRAL INDEX KEY:			0001473001

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51357
		FILM NUMBER:		10503280

	MAIL ADDRESS:	
		STREET 1:		C/O STADIUM CAPITAL MANAGEMENT, LLC
		STREET 2:		19785 VILLAGE OFFICE COURT, SUITE 101
		CITY:			BEND
		STATE:			OR
		ZIP:			97702

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SEAVER ALEXANDER M
		CENTRAL INDEX KEY:			0001473106

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51357
		FILM NUMBER:		10503279

	MAIL ADDRESS:	
		STREET 1:		C/O STADIUM CAPITAL MANAGEMENT, LLC
		STREET 2:		19785 VILLAGE OFFICE COURT, SUITE 101
		CITY:			BEND
		STATE:			OR
		ZIP:			97702

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Builders FirstSource, Inc.
		CENTRAL INDEX KEY:			0001316835
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-LUMBER & OTHER BUILDING MATERIALS DEALERS [5211]
		IRS NUMBER:				522084569
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2001 BRYAN STREET, SUITE 1600
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75201
		BUSINESS PHONE:		(214) 880-3500

	MAIL ADDRESS:	
		STREET 1:		2001 BRYAN STREET, SUITE 1600
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75201

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STADIUM CAPITAL MANAGEMENT LLC
		CENTRAL INDEX KEY:			0001105087
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51357
		FILM NUMBER:		10503281

	BUSINESS ADDRESS:	
		STREET 1:		19785 VILLAGE OFFICE COURT
		STREET 2:		STE 101
		CITY:			BEND
		STATE:			OR
		ZIP:			97702
		BUSINESS PHONE:		6503214000

	MAIL ADDRESS:	
		STREET 1:		19785 VILLAGE OFFICE COURT
		STREET 2:		STE 101
		CITY:			BEND
		STATE:			OR
		ZIP:			97702
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-12-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001316835</issuerCik>
        <issuerName>Builders FirstSource, Inc.</issuerName>
        <issuerTradingSymbol>BLDRR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001105087</rptOwnerCik>
            <rptOwnerName>STADIUM CAPITAL MANAGEMENT LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>19785 VILLAGE OFFICE COURT</rptOwnerStreet1>
            <rptOwnerStreet2>STE 101</rptOwnerStreet2>
            <rptOwnerCity>BEND</rptOwnerCity>
            <rptOwnerState>OR</rptOwnerState>
            <rptOwnerZipCode>97702</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001473001</rptOwnerCik>
            <rptOwnerName>KENT BRADLEY R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O STADIUM CAPITAL MANAGEMENT, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>19785 VILLAGE OFFICE COURT, SUITE 101</rptOwnerStreet2>
            <rptOwnerCity>BEND</rptOwnerCity>
            <rptOwnerState>OR</rptOwnerState>
            <rptOwnerZipCode>97702</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001473106</rptOwnerCik>
            <rptOwnerName>SEAVER ALEXANDER M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O STADIUM CAPITAL MANAGEMENT, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>19785 VILLAGE OFFICE COURT, SUITE 101</rptOwnerStreet2>
            <rptOwnerCity>BEND</rptOwnerCity>
            <rptOwnerState>OR</rptOwnerState>
            <rptOwnerZipCode>97702</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Subscription Rights (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>3.5</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-12-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.42</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2009-12-14</value>
            </exerciseDate>
            <expirationDate>
                <value>2010-01-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>100</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8647133</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The securities reported as beneficially owned by Stadium Capital Management, LLC (&quot;SCM&quot;), Bradley R. Kent (&quot;Kent&quot;) and Alexander M. Seaver (&quot;Seaver&quot;) on this Form 4 include securities also beneficially owned by investment advisory clients of SCM, including investment limited partnerships (the &quot;Funds&quot;) of which SCM is the general partner and investment adviser.  Kent and Seaver are the Managers of SCM.</footnote>
        <footnote id="F2">SCM, Kent and Seaver disclaim membership in a group, within the meaning of Rule 13d-5(b) and Rule 16a-1(a)(1) under the Securities Exchange Act of 1934, as amended, with any other person.  These securities are held directly by such investment advisory clients, including the Funds, for the benefit of such clients and the investors in those Funds.  SCM, Kent and Seaver disclaim beneficial ownership of such securities, except to the extent of their pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Stadium Capital Management, LLC by Bradley R. Kent, Manager</signatureName>
        <signatureDate>2010-01-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Bradley R. Kent</signatureName>
        <signatureDate>2010-01-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Alexander M. Seaver</signatureName>
        <signatureDate>2010-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----